Mechanisms convert forces into movement; structures resist forces to maintain stability. Deployable structures are, in effect, hybrids embodying both structural and mechanical behaviors.
In general, there are two types of deployable structures: those comprised of mechanical linkages, and those based on folding principles similar to origami shapes. Each type utilizes a different approach to material composition and fabrication techniques. Beyond considerations of physical construction, there are significant differences between each type in terms of their geometric organization and kinematic constraints.
What are the comparative advantages mechanical vs. origami-based structures?As a broad generalization, linkage based structures give the designer more freedom to select and optimize both mechanical performance and spatial configurations. There are fewer constraints in configuring link-joint arrangements of mechanical assemblies than in folding sheet-hinge arrangements. This freedom increases the ease in achieving both strength and controlled movement by incorporating structurally favorable shapes, optimized boundary conditions and kinematically redundant networks.
Nonetheless, origami-type deployable structures have significant advantages as well. One advantage is that surface and structure are, in effect, one entity, eliminating the need to add additional covering or cladding. A second benefit is that the cost of construction is economical. Manufacture can be efficiently performed by 2D sheet-based machinery such as laser-cutters or water-jets. Plates and hinges may be developed as material laminates and assembly may be minimized through simple folding processes.
This invention discloses a novel and unique class of folding mechanisms that combine benefits of both mechanical and origami approaches. Structures built according to this system have an origami-like folded construction. Yet at the same time, like many mechanically deployable structures, they are comprised of synchronized linkages that can be arranged in wide variety of structural compositions.
Structures built according to this invention are based on folding units that correspond to various polyhedral shapes. Units can be assembled into three dimensional lattice-like assemblies that maintain a high degree of synchronization and structural integrity during folding.